About Tcl/Tk

There are probably as many reasons why people use Tcl/Tk as there are
Tcl developers, but a number of reasons keep coming up again and again.

Rapid development

The most important reason why people use Tcl is that it gets their
job done faster. In many cases you can implement applications 5-10x
faster with Tcl than with other languages, especially if the application
involves GUIs, string-handling, or integration. Once an application
is built in Tcl, it can also be evolved rapidly to meet changing needs.

Graphical user interfaces

With its Tk toolkit, Tcl provides facilities for creating GUIs that
are incredibly simple yet remarkably powerful. For example, the Tk
canvas widget makes it easy to create displays with graphics, yet it
also provides powerful facilities such as bindings and tags. The text
widget provides sophisticated hypertext capabilities and more. Tk was
designed from the ground up for the rapid development inherent in
dynamic programming languages like Tcl; other, C++ based toolkits
lack the simplicity and power of Tk.

Cross-platform applications

Tcl/Tk runs on Windows, Macintosh, and nearly every imaginable
Unix platform. It provides high-level API's that let you write
code that works the same — everywhere — while Tcl/Tk
worries about respecting platform differences, such as native look and
feel for GUI's.

Easy to learn

Tcl is a very simple language. Experienced programmers can learn Tcl
and produce their first interesting application in just a few hours
or days. Casual programmers can also learn Tcl quickly.
Tcl is often
used in situations where experienced programmers create a base set
of facilities, and more casual programmers write Tcl scripts to customize
those facilities, create business rules, etc.

Mature but Evolving

Tcl and Tk have been under continuous, active development and use by
a large group of developers since the early 1990's. Because of this,
Tcl has had a long time to get right all those "finishing touches"
real applications depend on: rock solid reliability, rich
internationalization support, thread safety, high performance, portability,
integration, networking support and more. And because Tcl is constantly
evolving, new cutting edge features are being added all the time,
yet always with an eye to the consistent quality and concern for backwards
compatibility that Tcl has always been known for.

Extend, Embed and Integrate

Tcl is unmatched when it comes to integrating with other software.
You can easily include Tcl as an embedded scripting language in an
application, or make existing C, C++, or Java code look like it was
built right into Tcl. The same features make it easy to use Tcl as a
control language for special-purpose hardware or protocols, add a
new GUI or network interface to legacy applications, and more.

Deployment

Dynamic languages often make deployment harder, because you need to get
both the language interpreter and the application scripts onto the target
machine. Most dynamic languages provide tools to "compile" everything into
a single executable (Tcl has had that too, since about 1993). But Tcl/Tk
goes way beyond those simple solutions, using technologies like the Tcl
Virtual File System, and Starkits and Starpacks to make deployment more
flexible, powerful and transparent. Other options allow commercial
applications to protect their intellectual property, a rare capability
in dynamic languages.

Testing

Tcl is an ideal language to use for automated hardware and software
testing, and it may well be the dominant language used for this purpose.
With Tcl you can easily connect to testing hardware or internal APIs
of an application, invoke test functions, check the results, and report
errors. Tcl's interpreted implementation allows tests to be created
rapidly, and the tests can be saved as Tcl script files to reuse for
regression testing. If you are testing a software application, Tcl
allows you to connect directly to lower-level APIs within the application,
which provides much more precise and complete testing.

Network-aware applications

Tcl has a rich and powerful event-driven programming model that makes
network programming easy, allowing clients and servers to be created
with just a few lines of code. Networking, files, GUI events —
all work the same way, making for a consistent, easy to learn and
powerful programming style, without relying on extra libraries.

The Tcl community

Another attractive reason for using Tcl is the large and helpful community
of Tcl users and developers. The Tcl community is a constant source
of ideas, free extensions, applications, and technical support.

It's free!

Tcl is open source — freely available, meaning you can do anything
you want with it, including modifying it to suit your own needs or
incorporating it into commercial products, no strings attached.